1. Field of Invention
The invention relates to an electric drive control apparatus, an electric drive control method, and a program thereof.
2. Description of Related Art
There exists an electric drive apparatus that is mounted in a vehicle. For example, an electric motor vehicle as a type of electric vehicle. The electric drive apparatus causes the generation of a drive motor torque of a drive motor that acts as an electric machine. The drive motor torque is transferred to driving wheels so as to generate a driving force.
An electric drive apparatus is also mounted in a hybrid type vehicle, that is, an electric vehicle. The electric drive apparatus transfers a portion of an engine torque of an internal combustion engine, to an electric power generator (generator-motor) that acts as a first electric machine, and transfers the rest of the engine torque to the driving wheels. The electric drive apparatus has a planetary gear unit that includes a sun gear, a ring gear and a carrier. The carrier and the engine are connected, and the ring gear and the driving wheels are connected, and the sun gear and the generator are connected. Rotation output from the ring gear and a drive motor that acts as a second electric machine is transferred to the driving wheels to generate a driving force.
In the generator and the drive motor, a rotor is rotatably disposed and has a magnetic pole pair formed by a permanent magnet having a north pole and a south pole. Furthermore, a stator is disposed radially outward of the rotor, and is equipped with U-phase, V-phase and W-phase stator coils.
The aforementioned electric vehicle is provided with a drive motor control apparatus and the aforementioned hybrid type vehicle is provided with a generator control apparatus and a drive motor control apparatus as electric machine control apparatuses. Pulse width modulation signals of the U phase, the V phase and the W phase generated by the generator control apparatus and the drive motor control apparatus are sent to an inverter. The inverter generates phase electric currents, that is, currents of the U phase, the V phase and the W phase. The phase currents are then supplied to the stator coils so as to perform an asynchronous PWM control, whereby the drive motor is driven to generate drive motor torque or the generator is driven to generate generator torque.
In the drive motor control apparatus, for example, a feedback control based on a vector control computation is executed on a d-q axes model. In this model, the d axis is defined in a direction of the magnetic pole pair of the rotor and the q axis is defined in a direction perpendicular to the d axis. To that end, the drive motor control apparatus detects the electric current supplied to each stator coil, the magnetic pole position of the rotor, and the DC voltage at an input side of the inverter, for example. The apparatus then converts the detected currents into a d-axis current and a q-axis current on the basis of the magnetic pole position, and computes a d-axis current instruction value and a q-axis current instruction value that indicate a target value of the d-axis current and a target value of the q-axis current on the basis of the DC voltage. The drive motor control apparatus operates so that a deviation between the d-axis current and the d-axis current instruction value and a deviation between the q-axis current and the q-axis current instruction value become zero (see, for example, Japanese Patent Application Laid-Open Publication No. HEI 5-130710).